925 resultados para photocopied journal articles and book chapters


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The article addresses the questions, What do children in urban areas do on Saturdays? What types of organizational resources do they have access to? Does this vary by social class? Using diary data on children's activities on Saturdays in the Phoenix-Mesa-Scottsdale metropolitan area, the authors describe the different types of venues (households, businesses, public space, associations, charities, congregations, and government/tribal agencies) that served different types of children. They find that the likelihood of using a charity or business rather than a government or tribal provider increased with family income. Also, the likelihood of using a congregation or a government facility rather than a business, charity, or household increased with being Hispanic. The authors discuss the implications for the urban division of labor on Saturdays and offer research questions that need further investigation.

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This article explores the role of political context in shaping economic biases in representation-the degree to which wealthy citizens' views are more strongly represented than poorer citizens' views in the choices of policymakers. I develop a general model that explains why poorer citizens will be better represented relative to the rich in certain political contexts than others, arguing that the relative representation of the poor will be stronger in contexts that make the views of the poor relevant and accessible to policymakers. I then derive several specific hypotheses that flow from this model and test these hypotheses through a study of the dyadic relationships between citizens and their representatives in the U.S. Congress. The results show that poorer citizens are better represented relative to the rich in Congressional districts that are electorally competitive, have low median incomes, have relatively equal distributions of incomes, have a significant organized labor presence, and are represented by Democrats.

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We consider analytic reproducing kernel Hilbert spaces H with orthonormal bases of the form {(a(n) + b(n)z)z(n) : n >= 0}. If b(n) = 0 for all n, then H is a diagonal space and multiplication by z, M-z, is a weighted shift. Our focus is on providing extensive classes of examples for which M-z is a bounded subnormal operator on a tridiagonal space H where b(n) not equal 0. The Aronszajn sum of H and (1 - z)H where H is either the Hardy space or the Bergman space on the disk are two such examples.

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This research explores the health insurance coverage of various Hispanic subgroups in comparison to non-Hispanic whites and blacks. The impact of immigration status is also considered as we hypothesize that nativity, duration, and naturalization tap a possible process of structural acculturation that increases access to insurance coverage for Hispanic groups. We find that the immigration variables impact the type of insurance reported. However, race/ethnic disparities continue to exist, with the various Hispanic subgroups more likely to report miscellaneous government health insurance or no health insurance coverage as compared to non-Hispanic whites.

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The binary H2SO4−H2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0−6. Because it is a strong acid−base system, H2SO4−NH2CH3 quickly forms a tightly bound HSO4−−NH3CH3+ complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4−NH2CH3 is −21.8 kcal mol−1 compared with −16.8 kcal mol−1 for H2SO4−NH3 and −12.8 kcal mol−1 for H2SO4−H2O. Adding one to two water molecules to the H2SO4−NH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n ≥ 3. However, the average number of water molecules around H2SO4−NH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity.

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Compared the service use patterns of older adults with varying levels of mental impairment, and assessed the effects of services received on their mental health status over a 1-yr period. Data were obtained from a US General Accounting Office (1977, 1979) study of 531 elderly persons (mean age 76.1 yrs), which included administration of a modified version of the Older Americans Resources and Services Multidimensional Functional Assessment Questionnaire. Ss were interviewed twice, 1 yr apart. 174 Ss were classified as having a mild psychiatric impairment, and 118 Ss had a severe psychiatric impairment. The existence of mental impairment was related to marital status, race, and level of education. Usage of mental health services was low, although mentally impaired Ss were more likely than unimpaired Ss to use social and medical services. Results also suggest that such services can have an important effect on the mental health of older persons.

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We present examples of isospectral operators that do not have the same heat content. Several of these examples are planar polygons that are isospectral for the Laplace operator with Dirichlet boundary conditions. These include examples with infinitely many components. Other planar examples have mixed Dirichlet and Neumann boundary conditions. We also consider Schrodinger operators acting in L-2[0,1] with Dirichlet boundary conditions, and show that an abundance of isospectral deformations do not preserve the heat content.

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During the sixteenth and seventeenth centuries, the excise taxes (Ungeld) paid by town residents on the consumption of beer, wine, mead and brandy represented the single most important source of civic revenue for many German cities. In a crisis, these taxes could spike to 70-80% of civic income. This paper examines civic budgets and 'behind-the-scenes' deliberations in a sample of towns in southern Germany in order to illuminate how decisions affecting consumer taxes were made. Even during the sobriety movements of the Reformation and post-Reformation period, tax income from drinkers remained attractive to city leaders because the bulk of the excise tax burden could easily be shifted away from privileged members of society and placed on the population at large. At the same time, governments had to maintain a careful balance between what they needed in order to govern and what the consumer market could bear, for high taxes on drinks were also targeted in many popular revolts. This led to nimble politicking by those responsible for tax decisions. Drink taxes were introduced, raised, lowered and otherwise manipulated based not only on shifting fashions and tastes but also on the degree of economic stress faced by the community. Where civic rulers were successful in striking the right balance, the rewards were considerable. The income from drink sales was a major factor in how the cities of the Empire survived the wars and other crises of the early modern period without going into so much debt that they lost their independence.

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We consider k-hyponormality and n-contractivity (k, n = 1, 2, ...) as "weak subnormalities" for a Hilbert space operator. It is known that k-hyponormality implies 2k-contractivity; we produce some classes of weighted shifts including a parameter for which membership in a certain n-contractive class is equivalent to k-hyponormality. We consider as well some extensions of these results to operators arising as restrictions of these shifts, or from linear combinations of the Berger measures associated with the shifts.

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We provide a new proof of Volberg's Theorem characterizing thin interpolating sequences as those for which the Gram matrix associated to the normalized reproducing kernels is a compact perturbation of the identity. In the same paper, Volberg characterized sequences for which the Gram matrix is a compact perturbation of a unitary as well as those for which the Gram matrix is a Schatten-2 class perturbation of a unitary operator. We extend this characterization from 2 to p, where 2 <= p <= infinity.

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Model-based calibration of steady-state engine operation is commonly performed with highly parameterized empirical models that are accurate but not very robust, particularly when predicting highly nonlinear responses such as diesel smoke emissions. To address this problem, and to boost the accuracy of more robust non-parametric methods to the same level, GT-Power was used to transform the empirical model input space into multiple input spaces that simplified the input-output relationship and improved the accuracy and robustness of smoke predictions made by three commonly used empirical modeling methods: Multivariate Regression, Neural Networks and the k-Nearest Neighbor method. The availability of multiple input spaces allowed the development of two committee techniques: a 'Simple Committee' technique that used averaged predictions from a set of 10 pre-selected input spaces chosen by the training data and the "Minimum Variance Committee" technique where the input spaces for each prediction were chosen on the basis of disagreement between the three modeling methods. This latter technique equalized the performance of the three modeling methods. The successively increasing improvements resulting from the use of a single best transformed input space (Best Combination Technique), Simple Committee Technique and Minimum Variance Committee Technique were verified with hypothesis testing. The transformed input spaces were also shown to improve outlier detection and to improve k-Nearest Neighbor performance when predicting dynamic emissions with steady-state training data. An unexpected finding was that the benefits of input space transformation were unaffected by changes in the hardware or the calibration of the underlying GT-Power model.

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Gregarine apicomplexans are a diverse group of single-celled parasites that have feeding stages (trophozoites) and gamonts that generally inhabit the extracellular spaces of invertebrate hosts living in marine, freshwater, and terrestrial environments. Inferences about the evolutionary morphology of gregarine apicomplexans are being incrementally refined by molecular phylogenetic data, which suggest that several traits associated with the feeding cells of gregarines arose by convergent evolution. The study reported here supports these inferences by showing how molecular data reveals traits that are phylogenetically misleading within the context of comparative morphology alone. We examined the ultrastructure and molecular phylogenetic positions of two gregarine species isolated from the spaghetti worm Thelepus japonicus: Selenidium terebellae Ray 1930 and S. melongena n. sp. The ultrastructural traits of S. terebellae were very similar to other species of Selenidium sensu stricto, such as having vermiform trophozoites with an apical complex, few epicytic folds, and a dense array of microtubules underlying the trilayered pellicle. By contrast, S. melongena n. sp. lacked a comparably discrete assembly of subpellicular microtubules, instead employing a system of fibrils beneath the cell surface that supported a relatively dense array of helically arranged epicytic folds. Molecular phylogenetic analyses of small subunit rDNA sequences derived from single-cell PCR unexpectedly demonstrated that these two gregarines are close sister species. The ultrastructural differences between these two species were consistent with the fact that S. terebellae infects the inner lining of the host intestines, and S. melongena n. sp. primarily inhabits the coelom, infecting the outside wall of the host intestine. Altogether, these data demonstrate a compelling case of niche partitioning and associated morphological divergence in marine gregarine apicomplexans. (C) 2014 Elsevier GmbH. All rights reserved.

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The binary H2SO4-H2O nucleation is one of the most important pathways by which aerosols form in the atmosphere, and the presence of ternary species like amines increases aerosol formation rates. In this study, we focus on the hydration of a ternary system of sulfuric acid (H2SO4), methylamine (NH2CH3), and up to six waters to evaluate its implications for aerosol formation. By combining molecular dynamics (MD) sampling with high-level ab initio calculations, we determine the thermodynamics of forming H2SO4(NH2CH3)(H2O)n, where n = 0-6. Because it is a strong acid-base system, H2SO4-NH2CH3 quickly forms a tightly bound HSO4(-)-NH3CH3(+) complex that condenses water more readily than H2SO4 alone. The electronic binding energy of H2SO4-NH2CH3 is -21.8 kcal mol(-1) compared with -16.8 kcal mol(-1) for H2SO4-NH3 and -12.8 kcal mol(-1) for H2SO4-H2O. Adding one to two water molecules to the H2SO4-NH2CH3 complex is more favorable than adding to H2SO4 alone, yet there is no systematic difference for n ≥ 3. However, the average number of water molecules around H2SO4-NH2CH3 is consistently higher than that of H2SO4, and it is fairly independent of temperature and relative humidity.

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Cautions that in developing training models in mental health and aging, psychologists must not overlook what experience has taught them about mental health intervention or what they know already about older adults. It is suggested that a life-span developmental view complements a community and preventive approach to the mental health needs of the elderly. Creation of a separate subspecialty of clinical geropsychology will not effectively serve older adults. What is needed is a synthesis ofalready existing expertise in areas such as life-span development, clinical psychology, and community psychology. This synthesis provides a conceptual foundation and set of intervention approaches on which to base training programs in mental health and aging.